Stability of plasma enzymes during storage.

For measurement of plasma enzyme stability, 18 specimens of whole blood, plasma, and serum from normal subjects were stored at different temperatures. Eight enzymes were assayed after different times of storage: acetytcholinesterase, pseudocholinesterase, glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase, lactic dehydrogenase, acid and alkaline phosphatases, and amylase. At _200 all enzymes except lactic dehydrogenase were stable for 8 days, while at 38#{176} all except amylase were unstable. At 4#{176} the stability of the enzymes differed in whole blood, plasma, and serum, with a tendency toward greater stability than is usually reported.